KeyError: Key 'slug' not found in Form

Hi,

I am trying to translate my model using django-modeltranslation and the SlugField is giving me a lot of trouble. I have successfully registered the fields for translation, as you can see in the db table description:

                                     Table "public.news_news"      Column    |           Type           |                       Modifiers                          --------------+--------------------------+--------------------------------------------------------   id           | integer                  | not null default nextval('news_news_id_seq'::regclass)   title        | character varying(255)   | not null   title_en     | character varying(255)   |    title_nb     | character varying(255)   |    slug         | character varying(50)    | not null   slug_en      | character varying(50)    |    slug_nb      | character varying(50)    |

But when I try to add a new News item, I am getting the following error:

Traceback: File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response    115.                         response = callback(request, *callback_args, **callback_kwargs) File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in wrapper    372.                 return self.admin_site.admin_view(view)(*args, **kwargs) File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view    91.                     response = view_func(request, *args, **kwargs) File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func    89.         response = view_func(request, *args, **kwargs) File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/contrib/admin/sites.py" in inner    202.             return view(request, *args, **kwargs) File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper    25.             return bound_func(*args, **kwargs) File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view    91.                     response = view_func(request, *args, **kwargs) File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func    21.                 return func(self, *args2, **kwargs2) File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/db/transaction.py" in inner    223.                 return func(*args, **kwargs) File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in add_view    1036.             model_admin=self) File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/contrib/admin/helpers.py" in __init__    35.         } for field_name, dependencies in prepopulated_fields.items()] File "/home/roberto/.virtualenvs/ve_news/local/lib/python2.7/site-packages/django/forms/forms.py" in __getitem__    111.             raise KeyError('Key %r not found in Form' % name)    Exception Type: KeyError at /en/admin/news/news/add/ Exception Value: u"Key 'slug' not found in Form"

My admin.py :

from cmsplugin_news.admin import NewsAdmin as OldNewsAdmin    class NewsAdmin(OldNewsAdmin, TranslationAdmin,):      fields = ('title', 'slug')      form = NewNewsForm

models.py:

class News(models.Model):      title = models.CharField(_('Title'), max_length=255)      slug = models.SlugField(          _('Slug'), unique_for_date='pub_date',      )

and forms.py:

class NewNewsForm(forms.ModelForm):      class Meta:          model = News          fields = ('title', 'slug', )

As well, this is my translation.py where I declare the fields that should be translated by django-modeltranslation. I suppose anyhow that the error is not here, as the fields are already translated in db:

class NewsTranslationOptions(TranslationOptions):      fields = ('title', 'slug', 'excerpt', 'content')    translator.register(News, NewsTranslationOptions)

Any help please? I am really stuck! Thanks!

Roberto